The use of robots in assembly and packaging is well known. In particular, robots have been used widely in automobile manufacturing and electronic components assembly. Robots can work all day, every day, without interruption, except for occasional maintenance and repair.
Known methods and apparatus for assembly and packaging using robots rely upon the substantial uniformity in size and shape among the objects to be assembled or packaged and their precise location. These known methods and apparatus are generally not effective with randomly positioned and randomly oriented objects. This is typically the case with objects that are deposited onto a conveyor belt, such as flat components that are asymmetrical about at least one axis. For these parts, the system must locate them on the moving conveyor belt and also determine their orientation. This requires a relatively sophisticated vision system. It also requires a method for choosing which of several objects on the belt should be picked up and in what order. These known methods are also generally not effective in placing objects onto a moving conveyor belt, especially if the placement is to a random position and a random orientation, or at least a variable position and a variable orientation.
While the robotic manufacture and assembly of objects that are randomly positioned with random orientations on a conveyor belt presents particular difficulties, this is also an area where robots are especially needed. Performing the necessary operations by hand is likely to require short repetitive hand motions which can cause carpaltunnel syndrome and other long-term disabilities.
Included in this field is the packaging of food such as cookies, crackers and candies which are usually of a random orientation and a random position on a belt as they are dispensed from an oven or other manufacturing facility. Sometimes the food must be placed onto another moving belt, such as a moving belt carrying the package. In other applications, an object such as a cookie on one moving belt must be placed on top of another object such as another cookie to make a cookie sandwich. Packaging food by robots is particularly attractive because it overcomes sensitive sanitation concerns related to hand packaging. The existing systems for robotic packaging of food, like most of the existing systems for other robotic applications, rely on an orderly presentation of the objects to be packaged and a uniform presentation of the packaging. For example, the food packaging device disclosed in U.S. Pat. No. 4,832,180 requires that the objects to be packaged be substantially the same size, arranged in a row, and an equal distance from each other.